The present invention relates to a device for recording information of the type mentioned in the preamble to the appended claim 1.
In recent years, the use of computers has increased among many very geographically mobile occupational groups. One reason for this is that one can work more efficiently by having direct access to a large amount of information while at the same time having good capabilities for processing new information simply and efficiently.
For this purpose, various types of portable computers have been developed. Equipped with suitable software, these types of computers provide excellent capabilities for processing and managing information in text as well as image format.
A drawback of these portable computers is that inputting information by the intermediary of a keyboard is often time-consuming in comparison with the time required for processing the information once it has been fed into the computer. In order to achieve faster and more efficient inputting, there have been attempts at finding simpler ways of feeding the information into the computer. In some cases, the text which is to be fed into the computer is replaced by a numerical code, for instance in the case of vehicle inspections. However, this requires more of the user, who has to keep track of several codes, which increases the risk of input errors.
In the daily work of many occupational groups there is a need for a simple way of putting together image and text information. Examples of this include various types of service and maintenance staff who work from some type of protocol and who wish to verify that a certain operation has been carried out; policemen at the site of an accident who wish to gather image data as well as personal data concerning witnesses, etc.; and researchers and other individuals whose work involves information retrieval and who wish to put together text and images from a number of different written documents.
In order to achieve more efficient inputting of information in these and similar situations one could use other input units, such as a scanner which records text information from a surface when it is passed over the same and a digital camera which takes pictures and stores them digitally so that they can be transferred to a computer for processing.
Scanners of both the stationary and the portable type are available. Stationary scanners are preferably used in connection with the recording of whole pages with printed text and image information, the scanner being passed over the page at a constant speed. The information is recorded by means of a light-sensitive sensor, which in stationary scanners often consists of a line sensor.
However, in most of the above situations, rather than the recording of a whole page of information a more selective recording of information is desired and, moreover, the scanner must also be easy to carry. For this reason, scanners of the hand-held type are much more interesting in these contexts. The sensors in these scanners can be either of the line type or of the two-dimensional type.
U.S. Pat. No. 4,949,391, for example, discloses a hand-held scanner for recording text. The scanner has a two-dimensional sensor, which records images of the underlying surface when the scanner is passed over the same.
Another hand-held scanner is described in U.S. Pat. No. 5,301,234. This scanner utilises a line sensor which records a sequence of vertical xe2x80x9cslicesxe2x80x9d of the characters and of the spaces between them when the scanner is passed over the characters on the substrate. The xe2x80x9cslicesxe2x80x9d are stored in the scanner as a digital bitmap. To enable the accurate recording of characters, the scanner is provided with position means in the form of a wheel which must be in contact with the underlying surface in connection with the recording of the characters to record the position of the scanner relative to the surface.
A drawback of using a computer, a scanner, and a digital camera at the same time is that the equipment becomes bulky and the user has to handle several units.
Thus, there is a need for equipment which is easy to handle, enabling fast and reliable recording of selective text and image information in situations of the kind described above in a format facilitating computer processing of the same at a later time.
The object of the present invention is to provide a solution to the above-mentioned problems by providing an improved device for recording information in text and image format.
This object is achieved according to the invention by a device having the features recited in the appended claim 1, with preferred embodiments in the appended claims 2-14.
The invention is based on the understanding that with a light-sensitive sensor with a two-dimensional sensor surface as the starting-point, a text recording function, i.e. a xe2x80x9cscanner functionxe2x80x9d, as well as an image recording function, i.e. a xe2x80x9ccamera functionxe2x80x9d, can be easily created in the same device. More specifically, the device is adjustable between a first mode, in which the device is adapted to essentially abut against and be passed over a surface for imaging the same by means of a plurality of images, and a second mode, in which the device is adapted to image an object located at a distance.
The device can be adjusted by the user or automatically by the device if, for example, it detects that the distance to an object within its field of vision changes more than a predetermined value. The adjustment involves the adaptation of the device in some manner, e.g. physically or with respect to software, to make it suitable for use in the mode in question.
The first mode, or the xe2x80x9cscanner modexe2x80x9d, is intended for recording information located on a surface over which the device can be passed. The surface need not be plane. It is sufficient that it is even enough to enable the device to be moved in contact with the surface or directly adjacent to the same. The information, which can be said to be xe2x80x9ctwo-dimensionalxe2x80x9d since it is located on a surface, can be composed of character sequences, e.g. one or several words or one or several sentences selected from a longer text. The characters can be letters, numbers, or other written characters or symbols. It is preferably stored in character-coded format. However, the information may also be composed of image information which is scanned by passing the device over the surface and recording a plurality of images of the image information.
The second mode is preferably used for recording xe2x80x9cthree-dimensionalxe2x80x9d information, i.e. when one is required to take pictures of objects. Preferably, in this mode, individual pictures are taken which are stored in image format. Naturally, this mode can also be used for taking pictures of surfaces from a distance, which are stored in image format.
Preferably, the same sensor is employed in both the first and the second mode, but it is also possible to use one sensor for each mode. In the latter case, the adjustment would involve changing the beam path in the device so that the imaging takes place with the aid of one sensor in the first mode and with the aid of the other sensor in the second mode. The beam path can be changed by adjusting one or more components in the device. Alternatively, a first opening with a first fixed beam path can be used in the first mode, and a second opening with a second fixed beam path can used in the second mode. Adjusting between the modes then comprises an adjustment of which sensor is activated for imaging.
It should be noted in this context that a two-dimensional sensor surface refers to the fact that the sensor surface must be able to image a surface with a matrix of pixels so that images with overlapping contents can be recorded.
Preferably, in the first mode, images with partially overlapping contents are recorded. The overlapping contents are used to put together the images to form a composite image, in which there is no duplication of content. Suitably, the putting-together is carried out with the aid of a signal-processing unit which, for example, may contain software for this purpose. By virtue of the fact that the overlapping content is used for putting together the images, the device need not contain any means, e.g. wheels, for recording the position of the device relative to the surface which is being imaged or for measuring the distance between the images. Moreover, the device can be moved at varying speeds while still permitting the images to be put together into a composite image.
The putting-together of the images is preferably carried out horizontally as well as vertically. This has the advantage that the device can be held at different angles and even be turned while being passed over the surface and yet the images can be put together well enough that the characters in the composite image can be identified and OCR processed.
The signal-processing unit preferably comprises software for identifying characters in the composite image and for storing the same in the device in character-coded format, preferably ASCII code. The character identification is advantageously carried out with the aid of a neural network. Storing in character-coded format requires considerably less memory space than if the same amount of information is stored, for example, as a bitmap image.
In order to project onto the sensor surface a clear image of the information to be recorded, i.e. the surface over which the device is passed in the first mode, or Of the object located at a distance in the second mode, the device preferably comprises at least one lens means, which is adjustable between a first position in the first mode and a second position in the second mode. In this way, two foci are provided for the device, i.e. two different imaging distances each providing a sharp image on the sensor surface. One focus is preferably used in the first mode where an object is located adjacent to the device and the other is preferably used in the second mode where an object is located at a distance from the device. The second position can suitably allow imaging of objects at distances of between 0.5 m and infinity. The different foci enable imaging of surfaces or objects at different distances from the device. The lens means may comprise one or more adjustable lenses. The device may contain one or more fixed lenses in addition to the one or more adjustable lenses. This embodiment is intended in the first place for the case where the device has a single light-sensitive sensor which is common for both modes.
In another embodiment, the device comprises a lens means, the position of which is variable for providing a variable focus or an autofocus function. This enables sharp imaging of an object located at an optional distance.
Furthermore, in an advantageous embodiment, the device is adapted to effect the imaging in the first mode with a lower resolution than the imaging in the second mode. This can, for example, be achieved in the first mode by making passive some of the sensor elements of the sensor or by saving only a part of the sensor values which are recorded by the sensor, or by using only a part of the saved sensor values in the subsequent processing of the images, such as in connection with the putting-together. The advantage of this embodiment is that it is possible to achieve faster, yet reliable, putting-together of the images in the first mode if their resolution is lower.
Moreover, the device advantageously comprises a transceiver for wireless communication with an external unit. In this way, information can be transferred between the device and, for example, an external computer. The transceiver can be an IR transceiver, a mobile radio transceiver, or some other suitable transceiver.
To make the device easy to handle in all types of is recording situations it is suitably of the hand-held type. This also expands its field of application considerably.
In a preferred embodiment, the device also comprises identification means for identifying the extent of the imaging. The identification means may, for example, comprise a display mounted on the device, or one or several luminous spots projected from the device onto the object for defining the extent of the imaging. By the fact that the user gets an idea of what the image of the object will look like once it is recorded, the chances of obtaining an accurate imaging result will be substantially better.